Abstract: An apparatus for treating waste material, particularly organic catering waste, includes a hopper having an outlet at a bottom part thereof; a comminuting device adjoining the hopper for receiving waste material from the hopper; a chamber having an upper portion and a lower portion; and a raising device having an inlet and an outlet. The outlet of the raising device opens into the hopper above the hopper outlet and into the upper portion of the chamber, whereby waste material lifted by the raising device is discharged in part into the hopper and in part into the upper portion of the chamber. The apparatus further has a supply device situated below an outlet of the comminuting device and in the lower portion of the chamber. The supply device advances waste material from an outlet of the comminuting device and from the lower portion of the chamber to the inlet of the raising device.